VMware: Enable vCenter SSL certificate validation

During https/ssl communication the server certificate of
a vCenter is not validated during https handshake process.
This patch will enable the certificate validation against root
certificate of the vCenter to validate the identity of that vCenter.
Nova, Cinder etc will need to specify the cacert parameter
for this to take effect.

Ported from Id: Ic24951630698068321bb62d3098de8344a35c5d0

Closes-Bug: #1276207
Co-Authored-By: Johnson koil raj <johnson.raj@hp.com>
Change-Id: I422e6d4df4e392334c0ce47e6f5b017a8c95f61a
Merge "VMware: Enable vCenter SSL certificate validation"